441 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Test cases for SL[AOU]B/page initialization at alloc/free time.4 */5#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt6 7#include <linux/init.h>8#include <linux/kernel.h>9#include <linux/mm.h>10#include <linux/module.h>11#include <linux/slab.h>12#include <linux/string.h>13#include <linux/vmalloc.h>14 15#define GARBAGE_INT (0x09A7BA9E)16#define GARBAGE_BYTE (0x9E)17 18#define REPORT_FAILURES_IN_FN() \19 do { \20 if (failures) \21 pr_info("%s failed %d out of %d times\n", \22 __func__, failures, num_tests); \23 else \24 pr_info("all %d tests in %s passed\n", \25 num_tests, __func__); \26 } while (0)27 28/* Calculate the number of uninitialized bytes in the buffer. */29static int __init count_nonzero_bytes(void *ptr, size_t size)30{31 int i, ret = 0;32 unsigned char *p = (unsigned char *)ptr;33 34 for (i = 0; i < size; i++)35 if (p[i])36 ret++;37 return ret;38}39 40/* Fill a buffer with garbage, skipping |skip| first bytes. */41static void __init fill_with_garbage_skip(void *ptr, int size, size_t skip)42{43 unsigned int *p = (unsigned int *)((char *)ptr + skip);44 int i = 0;45 46 WARN_ON(skip > size);47 size -= skip;48 49 while (size >= sizeof(*p)) {50 p[i] = GARBAGE_INT;51 i++;52 size -= sizeof(*p);53 }54 if (size)55 memset(&p[i], GARBAGE_BYTE, size);56}57 58static void __init fill_with_garbage(void *ptr, size_t size)59{60 fill_with_garbage_skip(ptr, size, 0);61}62 63static int __init do_alloc_pages_order(int order, int *total_failures)64{65 struct page *page;66 void *buf;67 size_t size = PAGE_SIZE << order;68 69 page = alloc_pages(GFP_KERNEL, order);70 if (!page)71 goto err;72 buf = page_address(page);73 fill_with_garbage(buf, size);74 __free_pages(page, order);75 76 page = alloc_pages(GFP_KERNEL, order);77 if (!page)78 goto err;79 buf = page_address(page);80 if (count_nonzero_bytes(buf, size))81 (*total_failures)++;82 fill_with_garbage(buf, size);83 __free_pages(page, order);84 return 1;85err:86 (*total_failures)++;87 return 1;88}89 90/* Test the page allocator by calling alloc_pages with different orders. */91static int __init test_pages(int *total_failures)92{93 int failures = 0, num_tests = 0;94 int i;95 96 for (i = 0; i < NR_PAGE_ORDERS; i++)97 num_tests += do_alloc_pages_order(i, &failures);98 99 REPORT_FAILURES_IN_FN();100 *total_failures += failures;101 return num_tests;102}103 104/* Test kmalloc() with given parameters. */105static int __init do_kmalloc_size(size_t size, int *total_failures)106{107 void *buf;108 109 buf = kmalloc(size, GFP_KERNEL);110 if (!buf)111 goto err;112 fill_with_garbage(buf, size);113 kfree(buf);114 115 buf = kmalloc(size, GFP_KERNEL);116 if (!buf)117 goto err;118 if (count_nonzero_bytes(buf, size))119 (*total_failures)++;120 fill_with_garbage(buf, size);121 kfree(buf);122 return 1;123err:124 (*total_failures)++;125 return 1;126}127 128/* Test vmalloc() with given parameters. */129static int __init do_vmalloc_size(size_t size, int *total_failures)130{131 void *buf;132 133 buf = vmalloc(size);134 if (!buf)135 goto err;136 fill_with_garbage(buf, size);137 vfree(buf);138 139 buf = vmalloc(size);140 if (!buf)141 goto err;142 if (count_nonzero_bytes(buf, size))143 (*total_failures)++;144 fill_with_garbage(buf, size);145 vfree(buf);146 return 1;147err:148 (*total_failures)++;149 return 1;150}151 152/* Test kmalloc()/vmalloc() by allocating objects of different sizes. */153static int __init test_kvmalloc(int *total_failures)154{155 int failures = 0, num_tests = 0;156 int i, size;157 158 for (i = 0; i < 20; i++) {159 size = 1 << i;160 num_tests += do_kmalloc_size(size, &failures);161 num_tests += do_vmalloc_size(size, &failures);162 }163 164 REPORT_FAILURES_IN_FN();165 *total_failures += failures;166 return num_tests;167}168 169#define CTOR_BYTES (sizeof(unsigned int))170#define CTOR_PATTERN (0x41414141)171/* Initialize the first 4 bytes of the object. */172static void test_ctor(void *obj)173{174 *(unsigned int *)obj = CTOR_PATTERN;175}176 177/*178 * Check the invariants for the buffer allocated from a slab cache.179 * If the cache has a test constructor, the first 4 bytes of the object must180 * always remain equal to CTOR_PATTERN.181 * If the cache isn't an RCU-typesafe one, or if the allocation is done with182 * __GFP_ZERO, then the object contents must be zeroed after allocation.183 * If the cache is an RCU-typesafe one, the object contents must never be184 * zeroed after the first use. This is checked by memcmp() in185 * do_kmem_cache_size().186 */187static bool __init check_buf(void *buf, int size, bool want_ctor,188 bool want_rcu, bool want_zero)189{190 int bytes;191 bool fail = false;192 193 bytes = count_nonzero_bytes(buf, size);194 WARN_ON(want_ctor && want_zero);195 if (want_zero)196 return bytes;197 if (want_ctor) {198 if (*(unsigned int *)buf != CTOR_PATTERN)199 fail = 1;200 } else {201 if (bytes)202 fail = !want_rcu;203 }204 return fail;205}206 207#define BULK_SIZE 100208static void *bulk_array[BULK_SIZE];209 210/*211 * Test kmem_cache with given parameters:212 * want_ctor - use a constructor;213 * want_rcu - use SLAB_TYPESAFE_BY_RCU;214 * want_zero - use __GFP_ZERO.215 */216static int __init do_kmem_cache_size(size_t size, bool want_ctor,217 bool want_rcu, bool want_zero,218 int *total_failures)219{220 struct kmem_cache *c;221 int iter;222 bool fail = false;223 gfp_t alloc_mask = GFP_KERNEL | (want_zero ? __GFP_ZERO : 0);224 void *buf, *buf_copy;225 226 c = kmem_cache_create("test_cache", size, 1,227 want_rcu ? SLAB_TYPESAFE_BY_RCU : 0,228 want_ctor ? test_ctor : NULL);229 for (iter = 0; iter < 10; iter++) {230 /* Do a test of bulk allocations */231 if (!want_rcu && !want_ctor) {232 int ret;233 234 ret = kmem_cache_alloc_bulk(c, alloc_mask, BULK_SIZE, bulk_array);235 if (!ret) {236 fail = true;237 } else {238 int i;239 for (i = 0; i < ret; i++)240 fail |= check_buf(bulk_array[i], size, want_ctor, want_rcu, want_zero);241 kmem_cache_free_bulk(c, ret, bulk_array);242 }243 }244 245 buf = kmem_cache_alloc(c, alloc_mask);246 /* Check that buf is zeroed, if it must be. */247 fail |= check_buf(buf, size, want_ctor, want_rcu, want_zero);248 fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0);249 250 if (!want_rcu) {251 kmem_cache_free(c, buf);252 continue;253 }254 255 /*256 * If this is an RCU cache, use a critical section to ensure we257 * can touch objects after they're freed.258 */259 rcu_read_lock();260 /*261 * Copy the buffer to check that it's not wiped on262 * free().263 */264 buf_copy = kmalloc(size, GFP_ATOMIC);265 if (buf_copy)266 memcpy(buf_copy, buf, size);267 268 kmem_cache_free(c, buf);269 /*270 * Check that |buf| is intact after kmem_cache_free().271 * |want_zero| is false, because we wrote garbage to272 * the buffer already.273 */274 fail |= check_buf(buf, size, want_ctor, want_rcu,275 false);276 if (buf_copy) {277 fail |= (bool)memcmp(buf, buf_copy, size);278 kfree(buf_copy);279 }280 rcu_read_unlock();281 }282 kmem_cache_destroy(c);283 284 *total_failures += fail;285 return 1;286}287 288/*289 * Check that the data written to an RCU-allocated object survives290 * reallocation.291 */292static int __init do_kmem_cache_rcu_persistent(int size, int *total_failures)293{294 struct kmem_cache *c;295 void *buf, *buf_contents, *saved_ptr;296 void **used_objects;297 int i, iter, maxiter = 1024;298 bool fail = false;299 300 c = kmem_cache_create("test_cache", size, size, SLAB_TYPESAFE_BY_RCU,301 NULL);302 buf = kmem_cache_alloc(c, GFP_KERNEL);303 if (!buf)304 goto out;305 saved_ptr = buf;306 fill_with_garbage(buf, size);307 buf_contents = kmalloc(size, GFP_KERNEL);308 if (!buf_contents) {309 kmem_cache_free(c, buf);310 goto out;311 }312 used_objects = kmalloc_array(maxiter, sizeof(void *), GFP_KERNEL);313 if (!used_objects) {314 kmem_cache_free(c, buf);315 kfree(buf_contents);316 goto out;317 }318 memcpy(buf_contents, buf, size);319 kmem_cache_free(c, buf);320 /*321 * Run for a fixed number of iterations. If we never hit saved_ptr,322 * assume the test passes.323 */324 for (iter = 0; iter < maxiter; iter++) {325 buf = kmem_cache_alloc(c, GFP_KERNEL);326 used_objects[iter] = buf;327 if (buf == saved_ptr) {328 fail = memcmp(buf_contents, buf, size);329 for (i = 0; i <= iter; i++)330 kmem_cache_free(c, used_objects[i]);331 goto free_out;332 }333 }334 335 for (iter = 0; iter < maxiter; iter++)336 kmem_cache_free(c, used_objects[iter]);337 338free_out:339 kfree(buf_contents);340 kfree(used_objects);341out:342 kmem_cache_destroy(c);343 *total_failures += fail;344 return 1;345}346 347static int __init do_kmem_cache_size_bulk(int size, int *total_failures)348{349 struct kmem_cache *c;350 int i, iter, maxiter = 1024;351 int num, bytes;352 bool fail = false;353 void *objects[10];354 355 c = kmem_cache_create("test_cache", size, size, 0, NULL);356 for (iter = 0; (iter < maxiter) && !fail; iter++) {357 num = kmem_cache_alloc_bulk(c, GFP_KERNEL, ARRAY_SIZE(objects),358 objects);359 for (i = 0; i < num; i++) {360 bytes = count_nonzero_bytes(objects[i], size);361 if (bytes)362 fail = true;363 fill_with_garbage(objects[i], size);364 }365 366 if (num)367 kmem_cache_free_bulk(c, num, objects);368 }369 kmem_cache_destroy(c);370 *total_failures += fail;371 return 1;372}373 374/*375 * Test kmem_cache allocation by creating caches of different sizes, with and376 * without constructors, with and without SLAB_TYPESAFE_BY_RCU.377 */378static int __init test_kmemcache(int *total_failures)379{380 int failures = 0, num_tests = 0;381 int i, flags, size;382 bool ctor, rcu, zero;383 384 for (i = 0; i < 10; i++) {385 size = 8 << i;386 for (flags = 0; flags < 8; flags++) {387 ctor = flags & 1;388 rcu = flags & 2;389 zero = flags & 4;390 if (ctor & zero)391 continue;392 num_tests += do_kmem_cache_size(size, ctor, rcu, zero,393 &failures);394 }395 num_tests += do_kmem_cache_size_bulk(size, &failures);396 }397 REPORT_FAILURES_IN_FN();398 *total_failures += failures;399 return num_tests;400}401 402/* Test the behavior of SLAB_TYPESAFE_BY_RCU caches of different sizes. */403static int __init test_rcu_persistent(int *total_failures)404{405 int failures = 0, num_tests = 0;406 int i, size;407 408 for (i = 0; i < 10; i++) {409 size = 8 << i;410 num_tests += do_kmem_cache_rcu_persistent(size, &failures);411 }412 REPORT_FAILURES_IN_FN();413 *total_failures += failures;414 return num_tests;415}416 417/*418 * Run the tests. Each test function returns the number of executed tests and419 * updates |failures| with the number of failed tests.420 */421static int __init test_meminit_init(void)422{423 int failures = 0, num_tests = 0;424 425 num_tests += test_pages(&failures);426 num_tests += test_kvmalloc(&failures);427 num_tests += test_kmemcache(&failures);428 num_tests += test_rcu_persistent(&failures);429 430 if (failures == 0)431 pr_info("all %d tests passed!\n", num_tests);432 else433 pr_info("failures: %d out of %d\n", failures, num_tests);434 435 return failures ? -EINVAL : 0;436}437module_init(test_meminit_init);438 439MODULE_DESCRIPTION("Test cases for SL[AOU]B/page initialization at alloc/free time");440MODULE_LICENSE("GPL");441